Local injection to sciatic nerve of dexmedetomidine reduces pain behaviors, SGCs activation, NGF expression and sympathetic sprouting in CCI rats.

Neuropathic pain has become an intractable health threat, with its profound effect on quality of life. Dorsal root ganglia (DRG) is evidenced to play a crucial role in neuropathic pain. The peripheral nociceptive afferents seem to be essential not only to initiate the process of neuropathic pain, but also to maintain and modulate it. Dexmedetomidine (DEX), a highly selective agonist of α2-adrenergic receptor (α2-AR), has provided significant analgesia in neuropathic pain. In the present study, we found that local injection to sciatic nerve of DEX alleviated heat hypersensitivity induced by chronic constriction injury (CCI). Western blotting revealed that DEX inhibited the over-expression of nerve growth factor (NGF) significantly. Immunohistofluorescence results showed that DEX inhibited glia cells activation and sympathetic sprouting simultaneously in DRG. Our study suggests that DEX attenuates neuropathic pain in CCI rats by down-regulation of satellite glial cells (SGCs) activation, NGF expression and sympathetic sprouting.

The effect of sevoflurane on the cognitive function of rats and its association with the inhibition of synaptic transmission.

To observe the effects of different concentrations of sevoflurane on synaptotagmin 1 (Syt1) expression, synaptic long term depression (LTD), and paired pulse depression (PPD) in the rat hippocampus as well as to investigate the association between these effects and the cognitive function of rats. A total of 24 male Sprague-Dawley (SD) rats were selected and randomly divided into 3 groups: the control group (group A), which inhaled air; group B, which inhaled 0.65 minimum alveolar concentration (MAC) sevoflurane for 2 h; and group C, which inhaled 1.30 MAC sevoflurane for 2 h. The subsequent experiments were performed after one day. (1) Y maze tests were performed, and the expression of Syt1 in hippocampal tissues was detected using western blot. (2) The changes in LTD and PPD in rat hippocampal slices were examined using electrophysiological techniques. Compared to the control group, the cognitive function was decreased and Syt1 expression in the hippocampus was significantly decreased in rats in the 1.30 MAC sevoflurane inhalation group. After 60 min of low frequency stimulation, the amplitudes of population spike (PS) potentials in rat hippocampal slices were significantly decreased. After induction of PPD, the P2/P1 ratio was significantly increased. No indicators in the 0.65 MAC sevoflurane inhalation group showed any significant changes. Inhalation of high concentrations of sevoflurane significantly reduced Syt1 protein levels in the rat hippocampus, significantly inhibited the release of presynaptic neurotransmitters, and reduced the efficiency of synaptic transmission, thus causing memory impairment.

The effect of sevoflurane on the expression of M1 acetylcholine receptor in the hippocampus and cognitive function of aged rats.

Our aim is to investigate the effect of 1.5 and 3.0% sevoflurane on the expression of M(1) acetylcholine receptor (mAChR M(1)) in the hippocampus and the cognitive function of aged rats. Forty Sprague-Dawley (SD) rats of 12-month old were randomly divided into five groups. All SD rats received 1.5 or 3.0% sevoflurane in a special glass anesthesia box for 2 h, respectively, except for the normal control group. Y-maze was used to test the ability of learning and memory after being received sevoflurane for 1 or 7 days at the same moment portion. The expression of mAChR M(1) in the hippocampus of rats was tested by RT-PCR. The results showed that 3% sevoflurane induced the decline of cognitive function and significantly decreased the mAChR M(1) expression at mRNA levels at 1 day in the 3.0% sevoflurane I group when compared with the normal control group. However, there was no significant difference among the other groups when compared with normal control group. Therefore, administration of sevoflurane might temporally affect the ability of cognitive function of rats through suppressing the mAChR M(1) expression at mRNA levels in hippocampus.

The effect of sevoflurane anesthesia on cognitive function and the expression of Insulin-like Growth Factor-1 in CA1 region of hippocampus in old rats.

To investigate the effects of sevoflurane on cognitive function in old Sprague-Dawley (SD) rats and the expression of insulin-like growth factor-1 (IGF-1) in CA1 region of hippocampus. Forty Sprague-Dawley rats of 12 months old were randomly divided into five groups: the normal control group; 1.5% sevoflurane I group (be tested after received 1.5% sevoflurane for 1 day); 1.5% sevoflurane II group (be tested after received 1.5% sevoflurane for 7 day); 3.0% sevoflurane I group (be tested after received 3.0% sevoflurane for 1 day) and 3.0% sevoflurane II group (be tested after received 3.0% sevoflurane for 7 day). All SD rats were received 1.5 or 3.0% sevoflurane in a special glass anesthesia box for 2 h respectively, except for the normal control group. Y-maze was used to test the ability of learning and memory after being received sevoflurane for 1 or 7 days at the same moment portion. The altered expression level of IGF-1 in the hippocampus was tested to compare its transcripts by RT-PCR analysis. The results showed that 3% sevoflurane induced the decline of cognitive function and significantly deceased the IGF-1 expression at mRNA levels at 1 day in the 3.0% sevoflurane I group when compared with the normal control group. However, there were no significant difference among the other groups when compared with normal control group. Therefore, administration of sevoflurane might temporally affect the ability of cognitive function of rats through suppressing the IGF-1 expression at mRNA levels in hippocampus.

DFT calculations on the structural stability and infrared spectroscopy of endohedral metallofullerenes.

Endohedral metallofullerenes M@C(24) (M = Li(0/+), Na(0/+), K(0/+), Be(0/2+), Mg(0/2+) and Ca(0/2+)) with different spin configurations have been systematically investigated using the hybrid DFT-B3PW91 functional in conjunction with 6-31 G(d) basis sets. Our theoretical studies show that Li@C(24), Be@C(24), Be(2+)@C(24), and Mg(2+)@C(24) are energetically favorable. In these endohedral metallofullerenes, only the encapsulated Be and Ca atoms can donate the electrons to the cage. With exception of Be(2+)@C(24), the energy gaps of other charged compounds are larger than that of corresponding neutral compounds. We also find that some endohedral metallofullerenes have high energy gaps, but they are unlikely to show high thermodynamic stability. Additionally, the vibrational frequencies and active infrared intensities are also used as evidence to identify these endohedral metallofullerenes.